Разработка системы формирования налоговой отчетности по крипто

Разработка системы формирования налоговой отчетности по крипто

Налоговая отчётность — финальный шаг в цикле крипто-учёта. Система должна преобразовать рассчитанные tax events в форматы, принимаемые налоговыми органами или готовые для передачи бухгалтеру.

Форматы по юрисдикциям

class TaxReportGenerator {
  // USA: IRS Form 8949 + Schedule D
  async generateUS(userId: string, taxYear: number): Promise<Buffer> {
    const events = await this.getTaxEvents(userId, taxYear);
    
    const shortTerm = events.filter(e => !e.isLongTerm && e.category === "disposal");
    const longTerm = events.filter(e => e.isLongTerm && e.category === "disposal");
    
    // Form 8949 строки
    const form8949Rows = events.filter(e => e.category === "disposal").map(e => ({
      description: `${e.amount} ${e.asset}`,
      dateAcquired: e.acquiredAt ? format(e.acquiredAt, "MM/dd/yyyy") : "Various",
      dateSold: format(e.disposedAt, "MM/dd/yyyy"),
      proceeds: e.proceedsUSD.toFixed(2),
      costBasis: e.costBasisUSD.toFixed(2),
      adjustments: "0",
      gainLoss: e.gainLossUSD.toFixed(2),
      code: e.isLongTerm ? "E" : "A", // код для brokerage reported
    }));
    
    const scheduleD = {
      shortTermTotal: { proceeds: sum(shortTerm, "proceedsUSD"), costBasis: sum(shortTerm, "costBasisUSD"), gainLoss: sum(shortTerm, "gainLossUSD") },
      longTermTotal: { proceeds: sum(longTerm, "proceedsUSD"), costBasis: sum(longTerm, "costBasisUSD"), gainLoss: sum(longTerm, "gainLossUSD") },
    };
    
    return this.pdf.generate("form8949", { rows: form8949Rows, scheduleD, taxYear, userId });
  }
  
  // UK: HMRC Capital Gains Summary
  async generateUK(userId: string, taxYear: string): Promise<Buffer> {
    // UK tax year: 6 April - 5 April
    const { from, to } = parseUKTaxYear(taxYear); // "2023-24"
    const events = await this.getTaxEvents(userId, null, from, to);
    
    // UK использует Section 104 pool, применяем UK rules
    const ukEvents = await this.applyUKPoolingRules(events);
    
    const summary = {
      taxYear,
      totalProceeds: sum(ukEvents, "proceeds"),
      allowableCosts: sum(ukEvents, "costBasis"),
      gainsBeforeLosses: sum(ukEvents.filter(e => e.gain > 0), "gain"),
      losses: Math.abs(sum(ukEvents.filter(e => e.gain < 0), "gain")),
      netGains: sum(ukEvents, "gain"),
      annualExemptAmount: 6000, // UK 2023-24 annual exempt amount
      taxableGain: Math.max(0, sum(ukEvents, "gain") - 6000),
    };
    
    return this.pdf.generate("hmrc_cgt", { summary, events: ukEvents, taxYear });
  }
  
  // Germany: Anlage SO
  async generateGermany(userId: string, taxYear: number): Promise<Buffer> {
    const events = await this.getTaxEvents(userId, taxYear);
    
    // Германия: tax free после 1 года владения
    const taxableEvents = events.filter(e => !e.isLongTerm);
    const exemptEvents = events.filter(e => e.isLongTerm);
    
    // Freigrenze €600: если все gains < €600 — не облагается
    const totalGain = sum(taxableEvents.filter(e => e.gain > 0), "gain");
    const exemptUnderFreigrenze = totalGain < 600;
    
    return this.pdf.generate("anlage_so", {
      taxableEvents,
      exemptEvents,
      totalGain,
      exemptUnderFreigrenze,
      taxYear,
    });
  }
  
  // CSV для бухгалтера (универсальный)
  async generateCSV(userId: string, taxYear: number): Promise<string> {
    const events = await this.getTaxEvents(userId, taxYear);
    
    const headers = [
      "Date", "Asset", "Type", "Amount", "Proceeds USD", "Cost Basis USD",
      "Gain/Loss USD", "Is Long Term", "Acquired At", "Holding Days", "Notes"
    ];
    
    const rows = events.map(e => [
      format(e.disposedAt, "yyyy-MM-dd"),
      e.asset,
      e.category,
      e.amount,
      e.proceedsUSD?.toFixed(2) ?? "",
      e.costBasisUSD?.toFixed(2) ?? "",
      e.gainLossUSD?.toFixed(2) ?? e.incomeUSD?.toFixed(2) ?? "",
      e.isLongTerm ?? "",
      e.acquiredAt ? format(e.acquiredAt, "yyyy-MM-dd") : "",
      e.holdingDays ?? "",
      e.notes ?? "",
    ]);
    
    return [headers, ...rows].map(r => r.join(",")).join("\n");
  }
}

Koinly-compatible export

Для пользователей кто хочет дальше импортировать в Koinly:

async function generateKoinlyCSV(transactions: UnifiedTransaction[]): Promise<string> {
  const headers = ["Date", "Sent Amount", "Sent Currency", "Received Amount", "Received Currency", 
                   "Fee Amount", "Fee Currency", "Net Worth Amount", "Net Worth Currency", 
                   "Label", "Description", "TxHash"];
  
  const rows = transactions.map(tx => [
    format(tx.timestamp, "yyyy-MM-dd HH:mm:ss"),
    tx.amountOut ?? "",
    tx.assetOut ?? "",
    tx.amountIn ?? "",
    tx.assetIn ?? "",
    tx.feeAmount ?? "",
    tx.feeCurrency ?? "",
    tx.valueUSD ?? "",
    "USD",
    mapToKoinlyLabel(tx.category),
    tx.notes ?? "",
    tx.txHash ?? "",
  ]);
  
  return [headers, ...rows].map(r => r.join(",")).join("\n");
}

Система формирования налоговой отчётности с поддержкой IRS 8949, HMRC CGT, Anlage SO и Koinly-compatible CSV — 3-4 недели разработки.